1. Field of the Invention
This invention relates to improvements in apparatus and methods for constructing metal building panels with arched portions from flat sheet material. The panels are connected to form a self-supporting building with seamed joints between adjacent panels.
2. Background and Prior Art
It is known in the prior art to make metal buildings from adjacent formed metal building panels which are arched or curved, assembled side-by-side and seamed together. See for example, Knudson U.S. Pat. No. 3,902,288 (1975) for a showing of such buildings in which the roof panels are completely curved or arched and extend to the foundation. In such buildings the roof panels continue as the side walls of the building and the basic building construction is in the shape of a continuous arch or semi-circle when viewed from the end. A machine for making the metal panels for such building in which the formed panels are corrugated not only on the side edges of the box, but also on the bottom to create the curvature, is shown in Knudson U.S. Pat. No. 3,842,647 (1974). A method of building the building by adjacent panels which are seamed together is disclosed in Knudson U.S. Pat. No. 3,967,430 (1976). A seamer for forming the seams between the adjacent panels of the prior Knudson patents is shown in Knudson U.S. Pat. No. 3,875,642 (1975). The prior art represented by the Knudson patents is owned and has been commercialized by M.I.C. Industries, Inc. of Reston, Virginia in its mobile K-Span.RTM. machines.
An apparatus and method for forming corrugated building panels using manually adjustable forms are disclosed in Howell U.S. Pat. No. 2,986,193 (1961) and U.S. Pat. No. 3,150,707 (1964).
An arched building construction in which the walls and roof are completely arched has advantages, but also a number of limitations. One limitation is the absence of vertical walls which limits the use of vertical space. Often users of metal buildings want vertical walls both for aesthetic purposes and to allow more use of space near the edges of the buildings. Additionally, known prior art machines had a limitation on the thickness of steel used in forming the metal panels, because of machine limitations. The basic size and strength of such metal buildings is also limited by local wind and live load limitations as established by building codes throughout the nation and the world. As these building code standards become more conservative, a builder is effectively limited to only certain size buildings. The complete arched building must be limited in size in order to prevent overloading such as could occur from extensive wind loads produced by hurricanes. However, when the total roof height is reduced to approximately one-fifth of the total building width, hurricane force winds do not affect the building as much because of reduced frontal area. Thus, there is a need in the art for a metal building formed of continuous panels which is not completely arched but has straight vertical walls while utilizing the economy of the seamed panel construction of the prior art. Such vertical wall buildings would satisfy a need in the art for space, economy, usefulness and strength.
In addition to the prior art discussed above, Knudson U.S. Pat. No. 4,039,063 (1977) discloses a run-out apparatus and method for handling formed panels to produce arched metal buildings. As shown in the patent, run-out tables can be positioned to collect the curved panels. Additional patents exist in the art for forming and assembling relatively wide panels for arched metal buildings, see Knudson U.S. Pat. Nos. 4,364,263 (1982) 4,505,143 (1985), 4,505,084 (1985) and the seamer therefor in Knudson U.S. Pat. No. 4,470,183 (1984). These patents are owned by and commercialized in M.I.C.'s Super Span.RTM. mobile metal forming machines. In the prior art the radius of the arch could only be adjusted by manual means. Furthermore, the radius of the arch could only be adjusted to a desired curvature when there was no material in the machine. The procedure for radius adjustment included setting dials to a reference number to form a predetermined length of metal then forming the metal and comparing it to a radius gauge that must be made from a plywood template or a similar radius measuring device. If after inserting a piece of metal in the machine and curving it, the radius is incorrect, the operator must dial in a new set of numbers and rely on experience and rules of thumb to help him achieve the proper radius. In order to achieve the proper curvature for arched panels, up to 500 pounds or more of metal may be wasted by bending them to the wrong curvature, depending on how skilled the machine operator is. Thus, there is need in the art to provide for automatically and controllably adjusting the radius of curvature and to be able to accomplish that with material in the machine, so that no material is wasted in reaching the desired curvature.
Another drawback in the prior art is that the dials set to control the radius of the panel independently operate on the top side of the panel or the bottom side. Failure to adjust the two dials properly will cause the curved panel to distort and produce panels which are unacceptable for building use and must be scrapped. Distortion is sometimes termed "corkscrewing." Thus, there is need in the art to allow automatic and continuous adjustment of the curvature of the panels by a semi-skilled operator.
Another deficiency in the prior art arched panel forming machines is that they do not produce straight sections and curved sections together on the same panel. Furthermore, straight panels formed separately and used as vertical wall building panels are weak because they are not crimped. In other words, with the existing technology, crimping just the side walls of the panels cannot be accomplished although there is a need in the art to provide for a crimping of the side walls of straight panels used as vertical building walls.
Furthermore, the prior known machines for producing arched metal building panels have main crimping rollers which when being adjusted separate from each other causing diminished contact area of the gears resulting in significant premature gear wear. Also, when the crimping rolls of the prior art become separated, it is very difficult to re-engage the gears without physically guiding them into position which requires the machine operator to adjust the machine with moving machine parts, which is unsafe. Furthermore, when the main rolls are separated and the gear teeth are so far out of mesh, the gear backlash is severe, causing the main crimpers to turn out of time with each other and results in unacceptable finished panels. There is a need in the art for an improved drive train of the main crimping rolls which eliminates the above-mentioned problems and allows for an extremely smooth, trouble-free automatic crimping operation.
In the prior art, the operation of the machine was manual and the hydraulic system was adequate, however, it is desirable to allow simultaneous use of components and automatic and continuous adjustment of the crimping operation while allowing the hydraulic control of the panel former, shear blade and other controls. Thus, there is a need in the art for automatic controls from a control panel so that a semi-skilled operator can automatically control the forming machine to produce panels of any desired curvature including portions which are straight and not curved.